Position Measurement & Control - April 2001 (S050C)

Contents

• Via Systems Help Prevent Headaches
• Application Corner
  • DATAQ Instruments DI-151RS
  • Cutting the Displacement Cable
  • Terminating the Displacement Cable
  • Repairs and Replacement Parts
  • Calibration Tool: Acceptance Test Data Sheet
  • Hybrid Potentiometer: What Is It?
• In Action
  • Precisely What Is A Stiff Breeze To A Tent?
  • UAV Flight Testing
  • Vehicle Dynamics Monitoring
  • Roof Shingle Manufacturing Equipment
• News You Can Use
  • After Hours Assistance
  • Product Return

Via Systems Help Prevent Headaches

With a federal mandate that 40% of their average vehicle production meet new side-impact regulations, auto-makers now have a new tool to help them test car interiors for compliance.

The 9-foot high by 9-foot wide, multi-axis Free Motion Head Form Impact System, from Brighton, MI-based Via Systems, uses Firstmark Controls position transducers to smack a 10-lb crash-dummy "head" into 16 different targets inside the car at 15 mph. The goal: to check if the design of the A and B pillars and other parts of the car's interior will soften the blow as required.

The "action" end of Via Systems' test system.

Via wanted a system with a rotary beam attached to the Z axis of the base unit. The beam would have a hockey puck-shaped disc that would hold the "head," which itself would have eight degrees of freedom. The design called for a base unit that would position the impactor beam and head inside the car, be heavy enough to remain stable while the impactor flies around the inside of the car, and hold speed and accuracy at 1% repeatability.

The design called for a system that would develop 600 lbs of thrust at 3 g in 50 milliseconds, 80 inches from the center line of the Z axis. Speed had to be 15 mph over 5.5 inches.

The first use of the product, Millbrook Proving Grounds in the United Kingdom, is now conducting about 15 to 20 tests per day with the Via system vs 6 with its previous system, which Millbrook engineers had to basically tear down to reposition it for each test.

Series 160 position transducer shown in the "head" of the Free Motion Head Form Impact System.

The Free Motion Head Form Impact System reduces testing costs.

Application Corner

The Application Corner is dedicated to answering your questions about using position transducers in specific applications. If you have an application question you would like answered, please let us know by phone, fax, e-mail, or mail.

Q. We generally feed the signal from your position transducers into a PLC. However, now we want to use a data recorder to do some analysis of our application. Do you have any suggestions?

A. DATAQ Instruments' DI-194RS product is a low-cost, easy-to-use data recorder that only requires a Windows-compatible PC and serial port. No external power supply is required.

To learn more about the DI-194RS, view the data sheet.

If you have different requirements, please contact us if you would like to know about other options.

Q. We needed to cut the displacement cable to length for our application. When we cut it, it frayed and spread apart. How do we prevent this?

A. As described in the Position Transducer Installation Guide (S023), before cutting the displacement cable, anneal it with a flame until it glows red (about 5 seconds with a lighter or candle held within 0.5 inches of the cable). Then, cut the cable with appropriate shears where the cable was annealed.

To view the Position Transducer Installation Guide, visit our Literature Room.

Q. I just received the position transducer. How do I crimp the copper sleeve to the displacement cable?

A. As described in the Position Transducer Installation Guide (S023), to crimp the copper sleeve to the displacement cable, loop the displacement cable through the copper sleeve, through the swivel or pull ring, and then back through the copper sleeve. Crimp the copper sleeve using a suitable crimping tool.

To view the Position Transducer Installation Guide, visit our Literature Room.

Q. The displacement cable was inadvertently cut during use. Are your position transducers repairable?

A. Yes, our products are generally fully repairable. If you would like to return a product for repair, please complete our Web-based RMA Number Request form and follow the instructions on that form.

Q. In a past issue of Position Measurement & Control, you provided calibraton procedures and showed a copy of your Acceptance Test Data Sheet (ATDS). Can you provide the calculations for the data and results on your ATDS?

A. To obtain a copy of our Acceptance Test Data Sheet in Excel 97 file format, please make a request using our Technical Support Request form. We will provide a generic version to you via e-mail.

Q. Your data sheets reference a "hybrid" potentiometer. What is a hybrid potentiometer?

A. A hybrid potentiometer has design elements of both a conductive plastic potentiometer and a wirewound potentiometer. It is a multi-turn wirewound potentiometer with a conductive plastic overlay. This design provides ease of manufacturing of the wirewound potentiometer with the long-life, low-noise, high-resolution characteristics of the conductive plastic potentiometer.

In Action

Every month we see numerous fascinating applications of our position transducers. Here are a few recent ones:

Exactly What Is A Stiff Breeze? Ever been in a tent on Mt. Everest in an 80-knot wind? Neither have we. But Series 160 position transducers have monitored the simulated effects on such tents in wind tunnels to determine their structural integrity.

UAV Flight Testing Series 150 and 170 units provide small size, accurate measurement, and environmental robustness required to monitor flight control surfaces on today's latest UAVs (uninhabited aerial vehicles) such as this Northrop Grumman Global Hawk high-altitude, long-endurance, unmanned reconnaissance air vehicle.

Vehicle Dynamics Testing Ever wonder why today's cars ride more smoothly than earlier models? One reason is vehicle dynamics testing using Series 161 position transducers to monitor the displacement between the vehicle's wheel and the vehicle's suspension. Using sturdy special-purpose suction cups and a wheel mount, the transducers offer fast installation and flexible use. The units are used to test everything from 220 mph Formula 1 racecars to 18-wheel trucks.

Roof Shingle Manufacturing Equipment Special Series 160 units constructed from stainless steel and using fiber-based displacement cable are being used by a major roofing shingle production factory for machine and process control. The transducers work 24/7 to control air flow actuators.

News You Can Use

Here are some updates and reminders regarding Firstmark Controls.

After Hours Assistance Need immediate help outside of our normal business hours of Monday - Thursday, 6:30 am to 5:00 pm (Pacific time)? Then, use our After Hours Assistance: 1-866-912-6232. We will assist you immediately with your question or issue.

Product Return Want to return a product for any reason? If so, complete our Web-based RMA Number Request form (reqrmano.htm) and follow the instructions on the form. By doing this, you will ensure your returned product is processed fast and accurately.

ISSN 1527-5108